The present invention relates to a gas analysis testing equipment and its testing method, and more especially, to an adsorbed gas content measuring instrument and its testing method.
Adsorbed gas means natural gas existent in gaps and cracks in a reservoir bed. In a normal natural gas reservoir bed, the adsorbed gas content is low, generally less than 20%; in an unconventional natural gas reservoir bed, the adsorbed gas content is high, the adsorbed gas contained in natural gas of a coal-seam gas reservoir bed is generally more than 85%, the adsorbed gas contained in natural gas of a shale gas reservoir bed is 20-85%. The content of adsorbed gas directly concerns the quality of the natural gas aggregates and the technology required during development. Especially, for normal natural gas such as coal-seam gas and shale gas, the adsorbed gas content is the key factor of reservoir bed evaluation, reservoir calculation, development and design. Therefore, the test of natural gas adsorbed gas content in gas contained sample has been widely applied in natural gas exploration and development, and has become an important aspect in natural gas resource development. Moreover, it is also broadly applied in metal mine exploitation, gas explosion prevention, environmental protection and monitoring, pedologic research, chemical industry and other fields.
There has been no testing equipment that is special for accurately measuring the adsorbed gas content at present. When the adsorbed gas content is tested by conventional testing equipment, it is required to place the gas contained sample in the sealed cylinder for analysis reaction, one end of the gas duct is connected with the interior of the puncture pinhead, the other end extends into the opening of the burette which is placed below the water tank liquid level with the opening downwards and bottom communicating with the gas collecting duct. Spring clamps or screw clamps can be set on the gas duct and gas collecting duct as desired.
The testing system assembled according to the abovementioned conventional lab equipment can basically meet the requirements of the natural gas for analysis reaction, collection and content measurement. However, in real-life application, we find that the testing system has the following defects:
1. Several segments of gas duct in corresponding length are required for the test; the duct must be filled up with air; when the air content is very low during analysis, the measuring result of the content of the analyzed gas collected by means of the existing testing system is very likely to be zero or has high deviation from the actual result; meanwhile, the air residue in the sealed cylinder is impossible to be emptied; fresh air is prone to be mixed during collection of analyzed gas; the testing system has a highly exposed area and is highly affected by the environment. Therefore, the testing accuracy is too inferior to meet the requirement for accurate measurement;
2. A long preparation time for the test is required and the operation process is complicated, so it is inconvenient for simultaneous execution and unsatisfactory for real-life needs;
3. In the test, it is required to test the sample to the initial temperature, but the existing testing system is incapable of accurately and stably controlling the corresponding testing temperature;
4. The equipment has high volume and is made of glass containers mainly, bearing less safety and stability. If carrying it to the site for testing, there are a lot of difficulties such as high volume, heavy height, proneness to be broken and damaged;
Therefore, the abovementioned equipment for measuring the adsorbed gas content and its testing method are to be further improved due to the inconvenience and defect in structure and usage. One of the key research subjects in this field is how to create a new adsorbed gas content measuring instrument with a compact structure, small volume, good gas tightness, accurate measurement, uniform heating and convenient & simple & rapid operation, easy to move and carry and suitable for field application, special for measuring and collecting various gases such as natural gas, especially small volume gases.